Improvement in bits for boring coal



S. H I PKINS, Jr.

Ets fm' Boring Gua.

Patented Jan. 14, 1873.

W. w W;

NI'I'D 'I'A'rns PATENT FFI.

STEPHEN HIPKIN S, JR., OF WHEELING, WEST VIRGINIA, ASSIGNOR OF ONE-` HALF OF HIS RIGHT TO RALPH HEATHERINGTON, OF SAME PLAC'E.

IMPROVEMENT IN BITS FOR BORING COAL, &c.

Specifieation formin g part of Letters Patent No. 134,805, dated January 14, 1873.

To all whom 'itmag/ concem:

Be it known that I, STEPHEN HIPKINs, Jr., of Wheeling, in the county of Ohio, and State of West Virginia, have invented certain new and useful Improvements in Boring-Bits, of which the following is a specification:

My invention 'relates to bits especially adapted for boring coal; and my said improveinent consists in combining, with separate bits fitted into dovetailed grooves on the body of the tool, means for effecting the longitudinal independent adjustment of the bits in said grooves to compensate for their wear and repeated sharpenin g and also in combinin g with separate bts, arranged around the body of a borin g-tool, a central borin g-bit, arrangedto extend beyond the ends of' the outer bits, to begin the work in advance of the others.

The accompanying drawing represents an elevation and end view of myimproved boringtool, the bits being made adj ustable.

My improvernent is intended especially for tools for boring coal; they may be used, however, if made sufficiently strong, for rock or other drillin g.

In the drawing I have shown the body a of the tool, providedv with four flanges or ridges, b, each provided With a dovetail-groove, e, in which dovetail backs of the bits d fit, which not only bore but cut with their straight edges. A stem, f, is formed on the rear end of the body a of the bit, which stem iits into the hollow bit-stock, to which the stem f may be sei cured by a key passing through a suitable opening in the bit-stock and an opening, g, in the stem f. From the rear end of the body a extend screw-openings, which connect with the dovetail-grooves e, and in which screws j bear against the inner ends of the bits d. By means of these screws each separate bit d may be adjusted beyond the body aindependently of the others, as it wears out and has to be ground down, and in..` this Way each bit may be used until there is not enough of it left to sharpen again. The body a; has an opening, i, in the end centrally with the bits d, in which the central bit ,h is secured,` so as to be removed and replaced by another when required. It extends beyond the others, and thus forms a central boring-cutter in advance of and within the circle formed by the others. By this arrangement a comparatively large hole is cut out, as the inner and outer boringbits fill the area of the circles described by each.

' It willbe readily understood that my improved bits do not bore with their ends only, but act also as' reainers, their longitudinal edges serving for that purpose. I need not further describe their advantages', as they will be appa-rent to any one having a knowledge of their use.

Having described my invention, I claim-- 1. The separate bits d fitted in dovetailgrooves e on the body a, and made adjustable by means of screws j, essentially as described.

2. In combinatiom-with the bits d, fitted in dovetailgrooves e in the periphery of the body a of boring-tool, a central bit, h, arranged to extend beyond the ends of the hits d, essentially as described.

STEPHEN HIPKINS, JR.

Witnesses:

EDwARD STEELE, IsAAo T. FREESE. 

